By Michael Skapinker

In Unilever's London headquarters, Gavin Neath, the consumer goods group's head of sustainability, takes a plastic contraption out of its cardboard box and places it on a table. It looks like a small and semi-transparent version of the vending machines that dispense drinks to office workers.

The device is called a Pureit - and it is a drinks dispensing machine of sorts. Developed by Hindustan Unilever, the company's Indian subsidiary, the Pureit provides drinking water from any source, however polluted, purifying it with a series of meshes, parasite and pesticide traps and a germ-killing battery kit, without the need for boiling and without the use of mains electricity.

The Pureit is an illustration of how multinationals are trying to get to grips with the notion of sustainability. In the US and western Europe, the priorities are reducing the amount of packaging, cutting fuel consumption and providing for consumers who want to be sure that their purchases have been produced in an ethical or environmentally friendly fashion.